- Palladium nanoparticles in carbon thin film-lined SBA-15 nanoreactors: Efficient heterogeneous catalysts for Suzuki-Miyaura cross coupling reaction in aqueous media
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Embedding Pd nanoparticles in carbon thin film-lined SBA-15 nanoreactors provides highly efficient catalysts for heterogeneous cross coupling reactions in aqueous media. No leaching or aggregation of Pd nanoparticles was found in these nanoreactors after reusing them several times. The carbon thin film lining of these nanoreactors was further confirmed with small molecular arene probing experiments.
- Zhi, Jian,Song, Depeng,Li, Zhiwen,Lei, Xia,Hu, Aiguo
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- Synthesis, characterization, and catalytic activity of (1,2-Diaryl) alkenylphosphine palladium complexes
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A series of (1,2-diaryl)alkenylphosphine palladium complexes have been designed and synthesized. The structures of palladium complexes depend on the ratio of amount of using PdCl2(CH3CN)2 and ligands. Additions of one equivalent of ligands afford dipalladium complexes [R1CH=CR2(PR2)PdCl2]2, R1 = R2 = R = Ph, (C1); R1 = R2 = p-tolyl, R = Ph, (C2); R1 = R2 = Ph, R = iPr, (C3). The dipalladium complexes (C1-C3) adopt a transoid conformation and existed as chlorine-bridged dimer with a single alkenylphosphine ligand at each Pd. Complex C1 is confirmed by X-ray crystallography. Additions of two equivalents of ligands afford monopalladium complexes {[R1CH=CR 2(PR2)]2PdCl2}, R1 = R2 = R = Ph, (C4); R1 = R2 = p-tolyl, R = Ph, (C5); R1 = R2 = Ph, R = iPr, (C6). The monopalladium complexes (C4-C6) adopt a transoid conformation with two alkenylphosphines. Complex C4 and C5 were confirmed by X-ray crystallography, respectively. For a crystal structure of complex C4, there are two independent palladium complexes in the asymmetric unit. All the complexes as a catalyst show good catalytic activity in Suzuki-Miyaura reaction.
- Xi, Chanjuan,Yu, Bingran,Yan, Xiaoyu,Tang, Ning
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- A Thiol-Functionalized UiO-67-Type Porous Single Crystal: Filling in the Synthetic Gap
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Thiol groups (-SH) offer versatile reactivity for functionalizing metal-organic frameworks, and yet thiol-equipped MOF solids remain underexplored due to synthetic challenges. Building on the recent breakthrough using benzyl mercaptan as the sulfur source and AlCl3 for uncovering the thiol function, we report on the thiol-equipped linker 3,3′-dimercaptobiphenyl-4,4′-dicarboxylic acid and its reaction with Zr(IV) ions to form a UiO-67-type MOF solid with distinct functionalities. The thiol-equipped UiO-67 scaffold shows substantial stability toward oxidation, e.g., it can be treated with 30% H2O2 to afford oxidation of the thiol to the strongly acidic sulfonic function while maintaining the ordered porous MOF structure. The thiol groups also effectively take up palladium(II) ions from solutions to allow for comparative studies on catalytic activities and to help elucidate how the spatial configuration of the thiol groups can be engineered to impact the performance of heterogeneous catalysis in the solid state. Comparative studies on the stability in the solventless (activated) state also help to highlight the steric factor in stabilizing UiO-67-type frameworks.
- Wong, Yan-Lung,Diao, Yingxue,He, Jun,Zeller, Matthias,Xu, Zhengtao
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- Synthesis, crystal structure, bioactivities of Ni(II), Cu(II), Co(II) and Pd(II) complexes with unsymmetrical thioether donor Schiff base: Phosphine free Pd(II) complex catalyzed Suzuki reaction
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A series of new Ni(II), Cu(II), Co(II) and Pd(II) complexes were synthesized from the reaction of thioether containing Schiff base ligand with corresponding metal salts by a simple environmentally benign procedure. The molecular formulae of ligand and their complexes are (C21H19NO2S)2,1, [Ni(C21H18NO2S)2]·CH3OH·H2O,2, [M(C21H18NO2S)2] (3 and 4), where (M = Cu(II) and Co(II)) and [Pd(C21H18NO2SCl)](5). All complexes were characterized by elemental analysis, FT-IR, UV–Vis spectroscopy and single crystal X-ray diffraction analysis. The ligand was characterized by same techniques and with 1H NMR spectroscopy. X-ray diffraction study reveals that copper complex adopts square planar geometry by coordinating via deprotonated hydroxyl oxygen, azomethine nitrogen of ligand to the copper centre and sulfur atoms remain unligated. As expected, nickel complex acquired a distorted octahedral geometry coordinating via deprotonated hydroxyl oxygen, azomethine nitrogen and thioether sulfur atoms of ligands. Interestingly, one water and one methanol molecule are attached at the out sphere of the nickel complex. Suzuki reaction was carried out in open atmospheric conditions using palladium complex as catalyst. The significant features of the palladium complex catalyzed reaction are good yield, simple workup procedure, easy purification and easy recovery technique of the catalyst. The reported palladium complex is phosphine free, air stable, moisture insensitive. The ligand and complexes show very good biological activities against Mycobacterium abscessus, Bacillus subtilis, Staphylococcus aureus, Proteus vulgaris, Mycobacterium smegmatis and Escherichia coli.
- Kalita, Mukul,Tamuli, Kashyap Jyoti,Barman, Pranjit,Sarma, Bipul,Baruah, Reshita,Deka Boruah, Hari Prasanna
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- Palladium supported on mesoporous silica via an in-situ method as an efficient catalyst for Suzuki-Miyaura coupling reactions
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Palladium-containing SBA-15 (Pd/SBA-15) was synthesized via an in situ approach. In this procedure, the hydrophobic solvent (CHCl3) was used as a transport medium to inject the Pd precursor (Pd(acetylacetonate) 2) directly into the inner core of the surfactant micelles. The resulting nanocomposite with 1.46 wt% Pd loading was achieved with highly dispersed and uniform palladium nanoparticles. The Pd/SBA-15 nanocomposite exhibited excellent catalytic activities and reuse ability in air for the Suzuki-Miyaura coupling reactions.
- Wang, Peiyu,Zhang, Guoheng,Liu, Liwei,Jiao, Haiyan,Deng, Xiaoyan,Zheng, Xiaoping
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- Effects of new NHC derivatives as ligands in the Suzuki–Miyaura reaction
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A series of NHC-derivative ligands was synthesized from bisbenzimidazole salts as the precursor of N-heterocyclic carbene with chalcogens, carbon disulfide, and phenyl isothiocyanate reagents. These new ligands were used in the Suzuki–Miyaura cross-coupling reaction in the presence of palladium(II) acetate. Particularly, it was observed a remarkable ligand activity with tellurourea (5).
- Y?lmaz, ülkü,Kü?ükbay, Hasan
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- Transition-metal-free Suzuki-type coupling reactions
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No metal required: The first transition-metal-free Suzuki-type coupling reaction was carried out in water by using tetrabutylammonium bromide (TBAB) as an additive (see scheme). Products were obtained in high yields with a wide range of aryl bromide substrates.
- Leadbeater, Nicholas E.,Marco, Maria
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- Nickel-Catalyzed Carbonylation of Difluoroalkyl Bromides with Arylboronic Acids
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A nickel-catalyzed carbonylative difluoroalkylation reaction with arylboronic acids under 1 atm of CO has been developed. The reaction proceeds under mild reaction conditions with high efficiency and high functional group tolerance. Preliminary mechanistic studies reveal that the arylacyl nickel complex is the key intermediate to circumvent the formation of labile fluoroacyl nickel, and bimetallic oxidative addition is likely the key step to facilitate the catalytic cycle.
- Zhao, Hai-Yang,Gao, Xing,Zhang, Shu,Zhang, Xingang
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- A polymer-supported salen-type palladium complex as a catalyst for the Suzuki-Miyaura cross-coupling reaction
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A salen-type palladium(II) complex was readily immobilised onto a Merrifield resin. The supported complex is an effective recyclable heterogeneous catalyst for the Suzuki cross-coupling reaction without the use of phosphine ligands. Leaching of the metal into solution from the supported catalyst proved negligible.
- Phan, Nam T.S.,Brown, David H.,Styring, Peter
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- Recycling Oryza sativa wastes into poly-imidazolium acetic acid-tagged nanocellulose Schiff base supported Pd nanoparticles for applications in cross-coupling reactions
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A green and sustainable heterogeneous nanocatalyst for the Suzuki reaction was fabricated by refining rice straw to ionic nanocellulose Schiff base (NCESB) which was employed for bio-reduction of Pd(II) into Pd nanoparticles (Pd NPs) and immobilization of these NPs to fabricate the desired nanocatalyst (NCESB@Pd). The TEM image revealed well-dispersed PdNPs with sizes of 5–23 nm. The new nanocatalyst displayed amazing activity in catalyzing coupling reactions of a wide range of halobenzenes with phenylboronic acid at 50 °C (reaction time 15–60 min) and even at room temperature (reaction time 120 min). The NCESB@Pd nanocatalyst exhibited excellent recyclability (up to five catalytic runs) without a significant loss of its activity or identity. Therefore, the new ionic nanocatalyst may open a new window for a novel generation of ionic low-cost green and highly effective nanocatalysts for organic transformation reactions.
- Elshaarawy, Reda F. M.,Yahya, Rana
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- Irradiation with UV Light Accelerates the MigitaKosugiStille Coupling Reaction in Air
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The Migita-Kosugi-Stille coupling reaction is a powerful method for the formation of carboncarbon bonds but often requires high temperatures that are not tolerated by all substrates. Herein, we report that irradiation with UV light accelerates this coupling reaction at room temperature in air in the presence of the commercially available PdCl2(PPh3)2 catalyst. This UVlight- assisted coupling reaction requires the presence of molecular oxygen, with mechanistic studies revealing that singlet oxygen is most likely involved in the reaction.
- Ishikawa, Takumi,Iwai, Tomohiro,Masai, Hiroshi,Murata, Mako,Terao, Jun
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supporting information
p. 124 - 126
(2022/02/14)
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- Biaryl Coupling of Aryldiazonium Salts and Arylboronic Acids Catalysed by Gold
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A gold-catalysed coupling of aryldiazonium salts with arylboronic acids is described. The reactions proceed in satisfactory yields under irradiation with blue LEDs in the presence of KF and a catalytic amount of ascorbic acid. Notably, 4-nitrobenzendiazonium tetrafluoroborate is sufficiently reactive to undergo the coupling with a variety of arylboronic acids in the absence of aryl radical initiators. The coupling is applicable for electron-donating and electron-withdrawing groups present at the para, ortho, and meta positions of both substrates.
- Medina-Mercado, Ignacio,Porcel, Susana
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- 'Awaken' aryl sulfonyl fluoride: a new partner in the Suzuki-Miyaura coupling reaction
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An example of the activation of the -SO2F group, which is traditionally considered a stable group even in the presence of a transition metal, is described using a novel partner in the Suzuki-Miyaura coupling reaction catalyzed by Pd(OAc)2 and Ruphos as ligands. The products showed good to outstanding yields and broad functional group compatibility under optimal conditions. The sequential synthesis of non-symmetric terphenyls and the gram grade process highlight the approach's synthetic utility. DFT calculations have shown that Pd0 prefers to insert between C-S bonds rather than S-F bonds. This journal is
- Ding, Chengrong,Guan, Chenfei,Miao, Huihui,Zhang, Guofu,Zhao, Yiyong
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supporting information
p. 3560 - 3564
(2022/03/07)
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- Ligand-free Suzuki-Miyaura cross-coupling with low Pd content: rapid development by a fluorescence-based high-throughput screening method
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Suzuki-Miyaura (SM) cross-coupling is one of the most effective strategies for carbon-carbon bond formation, but previous methods have several drawbacks, such as the requirement of complicated ligands, toxic organic solvents, and high-content-Pd catalysts. Thus, in this study, a highly efficient SM cross-coupling was developed using metal oxide catalysts: 0.02 mol% Pd, aqueous solvent, no ligand, and room temperature. Metal oxides containing low Pd content (ppm scale) were prepared by a simple co-precipitation method and used as a catalyst for the SM reaction. A fluorescence-based high-throughput screening (HTS) method was developed for the rapid evaluation of catalytic activity and reaction conditions. Among the various metal oxides, Pd/Fe2O3showed the highest activity for the SM reaction. After further optimization by HTS, various biaryl compounds were obtained under optimal conditions: Pd/Fe2O3(0.02 mol% Pd) in aqueous ethanol at mild temperature without any ligands.
- Lim, Taeho,Ryoo, Jeong Yup,Jang, Mingyeong,Han, Min Su
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p. 1009 - 1016
(2021/02/16)
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- Crosslinked polymer encapsulated palladium nanoparticles for catalytic reduction and Suzuki reactions in aqueous medium
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Acrylamide and N-isopropylacrylamide were copolymerized in the presence of a N,N-methylenebisacrylamide crosslinker to obtain poly(N-isopropylacrylamide-co-acrylamide) [P(NA)] polymer colloidal particles. Pd nano crystals with diameter of 4–8 nm were loaded into the [P(NA)] microgels by reduction of [PdCl4]-2 within dispersion of polymer microgels. The Pd NPs-loaded hybrid microgels were analysed by TEM, STEM, EDX and XRD. The catalytic ability of the Pd-[P(NA)] system was investigated towards reductive transformation of nitroarenes into corresponding aryl amines and Suzuki coupling transformation in a green solvent, H2O. The progress of catalytic reaction was examined by thin layer chromatography (TLC). Different reactants were effectively converted into their corresponding products with great to fabulous yields (extending from 75 to 97%) under gentle reaction conditions. The Pd-[P(NA)] catalyst is stable for long time and can be utilized numerous times without any notable loss in its catalytic action.
- Begum, Robina,Farooqi, Zahoor H.,Xiao, Jianliang,Ahmed, Ejaz,Sharif, Ahsan,Irfan, Ahmad
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- A recyclable self-supported nanoporous PdCu heterogeneous catalyst for aqueous Suzuki-Miyaura cross-coupling
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Nanoporous PdCu (NP-PdCu) was prepared by the dealloying strategy from a PdCuAl ternary alloy precursor and characterized systematically using SEM, TEM, XRD, and XPS. NP-PdCu was demonstrated to be a competent self-supported heterogenous catalyst for Suzuki-Miyaura cross-coupling, affording a series of synthetically valuable biaryl compounds in good to excellent yields. This catalyst could be easily separated from the productviacentrifugation and reused several times without obvious loss of catalytic performance.
- Chen, Jie,Du, Jialei,Liu, Fushan,Wang, Bin,Wang, Leichen,Xia, Hehuan,Xiang, Daili,Xu, Caixia,Zhang, Yuanyuan,Zhao, Yiwei
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supporting information
p. 11641 - 11644
(2021/11/12)
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- Construction of Bulky Ligand Libraries by Ru(II)-Catalyzed P(III)-Assisted ortho-C-H Secondary Alkylation
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Modification of commercially available biaryl monophosphine ligands via ruthenium(II)-catalyzed P(III)-directed-catalyzed ortho C-H secondary alkylation is described. The use of highly ring-strained norbornene as a secondary alkylating reagent is the key to this transformation. A series of highly bulky ligands with a norbornyl group were obtained in excellent yields. The modified ligands with secondary alkyl group outperformed common substituted phosphines in the Suzuki-Miyaura cross-coupling reaction at a ppm mole level of Pd catalyst.
- Li, Jia-Wei,Li, Ming,Liu, Yue-Jin,Tao, Jun-Yang,Wang, Liang-Neng,Zeng, Ming-Hua
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supporting information
p. 11915 - 11925
(2021/09/13)
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- GPR52 Antagonist Reduces Huntingtin Levels and Ameliorates Huntington's Disease-Related Phenotypes
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GPR52 is an orphan G protein-coupled receptor (GPCR) that has been recently implicated as a potential drug target of Huntington's disease (HD), an incurable monogenic neurodegenerative disorder. In this research, we found that striatal knockdown of GPR52 reduces mHTT levels in adult HdhQ140 mice, validating GPR52 as an HD target. In addition, we discovered a highly potent and specific GPR52 antagonist Comp-43 with an IC50 value of 0.63 μM by a structure-activity relationship (SAR) study. Further studies showed that Comp-43 reduces mHTT levels by targeting GPR52 and promotes survival of mouse primary striatal neurons. Moreover, in vivo study showed that Comp-43 not only reduces mHTT levels but also rescues HD-related phenotypes in HdhQ140 mice. Taken together, our study confirms that inhibition of GPR52 is a promising strategy for HD therapy, and the GPR52 antagonist Comp-43 might serve as a lead compound for further investigation.
- Wang, Congcong,Zhang, Yu-Fang,Guo, Shimeng,Zhao, Quan,Zeng, Yanping,Xie, Zhicheng,Xie, Xin,Lu, Boxun,Hu, Youhong
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p. 941 - 957
(2020/11/30)
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- Regioselective nitration of a biphenyl derivative to derive a fluorescent chloride sensor
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Methyl 2′-aminobiphenyl-4-carboxylate, an optical chloride sensor has been synthesized via Suzuki-Miyaura cross-coupling followed by regioselective nitration. In general biphenyl systems are prone to undergo poly nitration whenever they are subjected to nitration via different nitrating agents. But in this present work, a highly selective nitration in the 2′ position of methyl biphenyl-4-carboxylate was achieved using 70% HNO3 and acetic anhydride to derive 3. Upon reduction, 3 produces 4 which shows bright blue emission in different organic solvents. In presence of chloride ion the blue emission of the sensor changes to enhanced bright green emission. The chloride sensing has also been explored using other spectroscopic techniques such as 1H NMR, UV–vis spectroscopy, and theoretical study.
- Das, Tanmay,Mohar, Mrittika,Bag, Arijit
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supporting information
(2021/01/25)
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- Esterification or Thioesterification of Carboxylic Acids with Alcohols or Thiols Using Amphipathic Monolith-SO3H Resin
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We have developed a method for the esterification of carboxylic acids with alcohols using amphipathic, monolithic-resin bearing sulfonic acid moieties as cation exchange functions (monolith-SO3H). Monolith-SO3H efficiently catalyzed the esterification of aromatic and aliphatic carboxylic acids with various primary and secondary alcohols (1.55.0 equiv) in toluene at 6080 °C without the need to remove water generated during the reaction. The amphipathic property of monolith-SO3H facilitates dehydration due to its capacity for water absorption. This reaction was also applicable to thioesterification, wherein the corresponding thioesters were obtained in excellent yield using only 2.0 equiv of thiol in toluene, although heating at 120 °C was required. Moreover, monolith-SO3H was separable from the reaction mixtures by simple filtration and reused for at least five runs without decreasing the catalytic activity.
- Ichihara, Shuta,Ishida, Moeka,Ito, Ryo,Kato, Ayumu,Monguchi, Yasunari,Nakamura, Shinji,Park, Kwihwan,Sajiki, Hironao,Takada, Hitoshi,Wakayama, Fumika,Yamada, Tsuyoshi,Yamada, Yutaro
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p. 2702 - 2710
(2022/01/19)
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- A Practice of Reticular Chemistry: Construction of a Robust Mesoporous Palladium Metal-Organic Framework via Metal Metathesis
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Constructing stable palladium(II)-based metal-organic frameworks (MOFs) would unlock more opportunities for MOF chemistry, particularly toward applications in catalysis. However, their availability is limited by synthetic challenges due to the inertness of the Pd-ligand coordination bond, as well as the strong tendency of the Pd(II) source to be reduced under typical solvothermal conditions. Under the guidance of reticular chemistry, herein, we present the first example of an azolate Pd-MOF, BUT-33(Pd), obtained via a deuterated solvent-assisted metal metathesis. BUT-33(Pd) retains the underlying sodalite network and mesoporosity of the template BUT-33(Ni) and shows excellent chemical stability (resistance to an 8 M NaOH aqueous solution). With rich Pd(II) sites in the atomically precise distribution, it also demonstrates good performances as a heterogeneous Pd(II) catalyst in a wide application scope, including Suzuki/Heck coupling reactions and photocatalytic CO2 reduction to CH4. This work highlights a feasible approach to reticularly construct noble metal based MOFs via metal metathesis, in which various merits, including high chemical stability, large pores, and tunable functions, have been integrated for addressing challenging tasks.
- He, Tao,Kong, Xiang-Jing,Li, Jian-Rong,Lv, Xiu-Liang,Nie, Zuo-Ren,Si, Guang-Rui,Wang, Kecheng,Wu, Xue-Qian,Zhao, Chen,Zhou, Jian
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supporting information
p. 9901 - 9911
(2021/07/21)
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- Electrochemical esterification via oxidative coupling of aldehydes and alcohols
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An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
- Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
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supporting information
(2021/03/26)
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- Pillar[5]arene-Based 3D Hybrid Supramolecular Polymer for Green Catalysis in Water
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Pillar[n]arene-based supramolecular polymers have attracted great interest because of their tunable morphologies and external stimuli responsiveness. However, most of the investigations of supramolecular polymers previously reported were focused on their formation and transformation, and investigations on their applications are rare. Herein, we designed and prepared hybrid polymeric materials by incorporating Pd nanoparticles into a supramolecular polymer, constructed from a pillar[5]arene dimer and a three-arm guest. The obtained hybrid polymer was fully characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, scanning electron microscopy-energy-dispersive X-ray mapping, and X-ray diffraction technologies. Importantly, the hybrid supramolecular polymeric materials exhibited desirable catalytic activity for reductions of toxic nitroaromatics and C-C bond-forming Suzuki-Miyaura reaction in aqueous solution.
- Cai, Yan,Yan, Xin,Wang, Siyuan,Zhu, Zhiwen,Cen, Moupan,Ou, Changjin,Zhao, Qin,Yan, Qian,Wang, Jin,Yao, Yong
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p. 2883 - 2887
(2021/03/01)
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- Pd Nanoparticles Embedded Into MOF-808: Synthesis, Structural Characteristics, and Catalyst Properties for the Suzuki–Miyaura Coupling Reaction
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Abstract: A heterogeneous single-site catalyst Pd@MOF-808 was successfully synthesized by water-based, green synthesis procedure. The catalytic experiments exhibited the Pd@MOF-808 promoted efficiently the Suzuki–Miyaura coupling reaction without the assistance of organic phosphine ligands at atmospheric pressure conditions. The catalyst also could be applied in the gram-scale synthesis of industrially anti-inflanmatory analgestic Fenbufen. Graphic Abstract: [Figure not available: see fulltext.]
- Li, Tang,Pang, Wan,Wang, Jie,Zhang, Xiaoli,Zhao, Zesheng
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- 2-Phosphinoimidazole Ligands: N-H NHC or P-N Coordination Complexes in Palladium-Catalyzed Suzuki-Miyaura Reactions of Aryl Chlorides
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We report the synthesis of two palladium 2-(dialkylphosphino)imidazole complexes and demonstrate their activity as catalysts for Suzuki-Miyaura reactions with (hetero)aryl chlorides at room temperature. Our mechanistic studies demonstrate that these palladium complexes exist as an equilibrium mixture between the P-N coordinated and N-H NHC forms of ligand. Our studies suggest that the N-H NHC form may be important for high catalytic activity in Suzuki-Miyaura reactions with aryl chlorides. These reactions proceed at or near room temperature in good to excellent yields. Heteroaryl chlorides are also reactive at lower catalyst loadings.
- Martinez, Erin E.,Larson, Alexandra J. S.,Fuller, Sydney K.,Petersen, Kathryn M.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 1560 - 1564
(2021/05/29)
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- Method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds
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The invention discloses a method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds. The method comprises the following steps: adding a secondary alcohol compound, an additive and a nitrogen-doped mesoporous carbon loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1 MPa and the reaction temperature to be 80-150 DEG C, and obtaining a product after the reaction to be the carboxylic ester compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the carboxylic ester compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
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Paragraph 0064-0065; 0092
(2021/06/02)
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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
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A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
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p. 6591 - 6597
(2021/09/10)
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- Mild Copper-Catalyzed Addition of Arylboronic Esters to Di- tert -butyl Dicarbonate: An Easy Access to Methyl Arylcarboxylates
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An efficient copper-catalyzed addition of arylboronic esters to (Boc) 2O was developed. The reaction can be conducted under exceedingly mild conditions and is compatible with a variety of synthetically relevant functional groups. It therefore represents a useful alternative route for the synthesis of methyl arylcarboxylates. A preliminary mechanistic study indicated the involvement of an addition-elimination mechanism.
- Xu, Jin-Di,Su, Xiao-Bo,Wang, Cai,Yao, Li-Wei,Liu, Jing-Hui,Hu, Guo-Qin
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supporting information
p. 833 - 837
(2021/02/26)
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- N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
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The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
- Wessig, Pablo,Krebs, Saskia
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supporting information
p. 6367 - 6374
(2021/09/29)
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- Bulky α-diimine palladium complexes supported graphene oxide as heterogeneous catalysts for Suzuki-Miyaura reaction
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To explore high efficiency of the Suzuki-Miyaura reactions, an easily prepared heterogeous palladium precatalysts bearing sterically bulky α-diimine was covalently supported on graphene oxide (GO). The characterization of supported palladium complex was discussed in detail. A simple and efficient protocol for Pd-catalyzed cross coupling was described, which revealed that the bulky α-diimine ligand is crucial to promote the CAr-CAr transformation. This immobilized system provides a straightforward access to a wide range of aryl bromides with excellent functional groups tolerance.
- Liang, Ying,Liu, Feng-Shou,Liu, Ning,Qiao, NiNa,Wang, ShaoHua
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- Protecting-group-free synthesis of hydroxyesters from amino alcohols
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The synthesis of hydroxyesters from carboxylic acids and unprotected amino alcohols in both continuous flow and batch processes is reported. The formation of a transient diazonium species with a dinitrite reagent is key in this transformation. The reaction conditions are compatible with a variety of functional groups.
- Joseph-Valcin, Eve-Marline,Lebel, Hélène,Reynard, Guillaume
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supporting information
p. 10938 - 10941
(2020/10/02)
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- Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
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An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
- Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
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supporting information
p. 17887 - 17896
(2020/08/19)
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- Integrating Reactors and Catalysts through Three-Dimensional Printing: Efficiency and Reusability of an Impregnated Palladium on Silica Monolith in Sonogashira and Suzuki Reactions
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For this work, an integrated system composed of a polypropylene reactor and a palladium on silica monolithic catalyst was designed and manufactured by 3D-printing. These devices are able to perform solution phase chemistry in a robotic orbital shaker. The capped reactor was obtained in its entirety by 3D-printing, using polypropylene and fused deposition modeling. The monolithic catalyst was also obtained by 3D-printing -robocasting- of a silica support, sintering and subsequent palladium deposition through the wet impregnation method. The catalytic efficiency in Sonogashira or Suzuki reactions as well as the recyclability of the entire system – catalyst+reactor – were studied. The strong electrostatic adsorption (SEA) of the palladium on sintered silica and the reduced mechanical stress produced by the convenient adjustment of the catalyst into the polypropylene reactor makes the catalytic system reusable without significant loss of catalytic activity.
- Díaz-Marta, Antonio S.,Ya?ez, Susana,Lasorsa, Eliana,Pacheco, Patricia,Tubío, Carmen R.,Rivas, José,Pi?eiro, Yolanda,Gómez, Manuel A. Gonzalez,Amorín, Manuel,Guitián, Francisco,Coelho, Alberto
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p. 1762 - 1771
(2020/02/15)
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- Pd@COF-QA: A phase transfer composite catalyst for aqueous Suzuki-Miyaura coupling reaction
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A Pd NP-loaded and paraffin-chain quaternary ammonium salt-decorated covalent organic framework, Pd@COF-QA, and its chitosan aerogel-based continuous flow-through reactor, which could be an excellent phase transfer catalyst to promote the aqueous Suzuki-Miyaura coupling reaction, is reported.
- Wang, Jian-Cheng,Liu, Cong-Xue,Kan, Xuan,Wu, Xiao-Wei,Kan, Jing-Lan,Dong, Yu-Bin
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p. 1150 - 1155
(2020/03/11)
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- Ni-catalyzed direct alcoholysis of N-acylpyrrole-type tertiary amides under mild conditions
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N-Acylpyrrole-type amides are a class of versatile building blocks in asymmetric synthesis. We report that by employing Ni(COD)2/2,2′-bipyridine (5 mol%) catalytic system, the direct, catalytic alcoholysis of N-acylpyrrole-type aromatic and aliphatic amides with both primary and secondary alcohols can be achieved efficiently under very mild conditions (rt, 1 h) even at gram scale. By increasing the catalyst loading to 10 mol%, prolonging reaction time (18 h), and/or elevating reaction temperature to 50 °C/80 °C, the reaction could be extended to both complex and hindered N-acylpyrroles as well as to N-acylpyrazoles, Nacylindoles, and to other (functionalized) primary and secondary alcohols. In all cases, only 1.5 equiv. of alcohol were used. The value of the method has been demonstrated by the racemization-free, catalytic alcoholysis of chiral amides yielded from other asymmetric methodologies.
- Chen, Hang,Chen, Dong-Huang,Huang, Pei-Qiang
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p. 370 - 376
(2020/03/03)
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- Palladium-Catalyzed, Copper(I)-Promoted Methoxycarbonylation of Arylboronic Acids with O-Methyl S-Aryl Thiocarbonates
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Here, we report O-methyl S-aryl thiocarbonates as a versatile esterification reagent for palladium-catalyzed methoxycarbonylation of arylboronic acid in the presence of copper(I) thiophene-2-carboxylate (CuTC). The reaction condition is mild, and a variety of substituents including sensitive-Cl,-Br, and free-NH2 could be tolerated. Further applications in the late-stage esterification of some pharmaceutical drugs demonstrate the broad utility of this method.
- Cao, Ya-Fang,Li, Ling-Jun,Liu, Min,Xu, Hui,Dai, Hui-Xiong
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p. 4475 - 4481
(2020/04/10)
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- Palladium Supported on Silk Fibroin for Suzuki–Miyaura Cross-Coupling Reactions
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Silk fibroin supported Pd (Pd/SF) has been prepared and used as catalyst in Suzuki–Miyaura cross-coupling reactions in water/ethanol (4:1 v/v) mixture. The reactions proceed rapidly with aryl iodides and boronic acids with different electronic properties using low metal loading (0.38 mol-%). Pd/SF exhibits better recyclability compared to other biopolymer-supported Pd catalysts, up to nineteen cycles without loss of activity.
- Albano, Gianluigi,Farinola, Gianluca M.,Lo Presti, Marco,Milella, Antonella,Omenetto, Fiorenzo G.,Rizzo, Giorgio
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supporting information
p. 6992 - 6996
(2020/11/30)
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- A Highly Efficient Monophosphine Ligand for Parts per Million Levels Pd-Catalyzed Suzuki–Miyaura Coupling of (Hetero)Aryl Chlorides
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A new indolylphosphine WK-phos has been synthesized for Pd-catalyzed Suzuki–Miyaura coupling of (hetero)aryl chlorides with (alkyl)arylboronic acids. Comprising this newly developed ligand with palladium(II) acetate, the resulting catalyst system was found to be highly effective in facilitating the reaction even when the catalyst loading reaches parts per million levels (e.g. 10 ppm). These examples represent one of the lowest catalyst loadings reported to date of employing monophosphine (e.g. Ar-PCy2) for Suzuki–Miyaura reactions. The ligand geometry has also been well-characterized by single-crystal X-ray crystallography.
- Choy, Pui Ying,Yuen, On Ying,Leung, Man Pan,Chow, Wing Kin,Kwong, Fuk Yee
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p. 2846 - 2853
(2020/04/09)
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- Design, synthesis and application of triazole ligands in suzuki miyaura cross coupling reaction of aryl chlorides
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DFT calculations have been demonstrated to be a valuable tool for the mechanistic study of reaction which is difficult to acquire from pure experimental techniques. Structural, electronic and coordination aspects of synthesized triazole ligands were investigated theoretically by structure optimization on Gaussian 09 package by DFT approach at B3LYP/6-31G (d, p). HOMO-LUMO energy gaps correlated to its chemical reactivity and this information applied to interpret the role of ligand in the formation of ligand-metal complex. Electron rich environment around the triazole core stabilized the HOMO orbital and made these electrons available to form complex with Pd centre. The DFT calculations provide a plausible mechanism for the reaction that is consistent with the available experimental facts. A series of triazole ligands have been synthesized via efficient 1,3-dipolar cycloaddition of readily available azide and alkynes for coordination to Pd centre. Characterization of all the synthesized compounds was done by FTIR, 1H NMR, 13C NMR and HRMS. Their ligand-Pd complexes provided excellent yields in the Suzuki-Miyaura coupling reactions (up to 92% yield) of unactivated aryl chlorides. Ligand 4-(2,6-dimethoxyphenyl)-1-phenyl-1H-1,2,3-triazole (L2) was found to be most effective ligand because of electron donating 2,6 dimethoxy phenyl moiety attached to triazole ring at 4-position that facilitated the formation of electron rich ligand-catalyst complex. The complex favoured the oxidative addition step of Pd across the aryl chloride substrate and thus allowed for the development of highly active ligand-catalyst system for Suzuki reaction. During computational analysis, 4-(2,6-dimethoxyphenyl)-1-phenyl-1H-1,2,3-triazole (L2) also showed lowest band gap due to electron rich distribution pattern on the HOMO that are involve in ligand-Pd complex formation. Conclusively, these triazoles ligands were found to be more competent and attractive for palladium catalyst because of simplistic pathway for the synthesis of triazole motif and the ease of individual tuning of the substituents on triazole core or exocyclic to it.
- Jabeen, Sobia,Khera, Rasheed Ahmad,Iqbal, Javed,Asgher, Muhammad
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- Aerobic Oxidative Cleavage and Esterification of C(OH)–C Bonds
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C(OH)–C bonds are widely distributed in naturally renewable biomass, such as carbohydrates, lignin, and their platform molecules. Selective cleavage and functionalization of C(OH)–C bonds is an attractive strategy in terms of producing value-added chemicals from biomass. However, effective transformation of alcohols into esters by activation of C(OH)–C bonds has not been achieved so far. Herein, for the first time, we report selective cleavage and esterification of C(OH)–C bonds, catalyzed by inexpensive copper salts, using environmentally benign oxygen as the oxidant, to afford methyl esters in excellent yields. A diverse range of phenylethanol derivatives that contain C(OH)–C bonds were effectively converted into methyl benzoates. Detailed analysis revealed that the high efficiency and selectivity resulted mainly from the fact that, in addition to the major esterification reaction, the side products (e.g., olefins and acids) were also transformed in situ into esters in the reaction system. C(OH)–C bonds are widely distributed in naturally renewable biomass. In the context of developing future biorefineries, selective cleavage and functionalization of C(OH)–C bonds are crucial and represent an attractive strategy in terms of producing value-added chemical compounds from biomass resources. In the current manuscript, we report, for the first time, an effective and selective method for the cleavage and esterification of C(OH)–C bonds of alcohols to produce esters, by using environmentally benign O2 as the terminal oxidant and inexpensive commercially available copper salts as catalysts. Furthermore, a detailed mechanistic study revealed that, in addition to the major esterification route, side products (e.g., olefins and acids), which are inevitably generated under oxidative and basic conditions, were also simultaneously converted into esters, thus significantly improving the final yields of target ester products. Native lignin represents the only naturally sustainable aromatic resource. Transformation of native lignin into valuable aromatics would make a great contribution to our planet. We report, for the first time, the effective transformation of alcohols into esters by esterification of C(OH)–C bonds, which offers a new way for the simultaneous degradation and functionalization of lignin. This reaction promotes new explorations for biomass valorization.
- Liu, Mingyang,Zhang, Zhanrong,Yan, Jiang,Liu, Shuaishuai,Liu, Huizhen,Liu, Zhaotie,Wang, Weitao,He, Zhenhong,Han, Buxing
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supporting information
p. 3288 - 3296
(2020/10/20)
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- The Synthesis and Catalytic Activity of New Mixed NHC-Phosphite Nickel(0) Complexes
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Herein we describe the synthesis and isolation of the first low-valent NHC-phosphite nickel complexes of general formula Ni(NHC)[P(OAr)3]2. These three-coordinate Ni(0) compounds were fully characterized, including by X-ray crystallography that highlighted their trigonal planar geometry. The representative complex Ni(IMes)[P(OPh)3]2 was used to show that a phosphite ligand is readily substituted in the presence of an aldehyde or nitrile. These stoichiometric studies then led to an investigation of their catalytic properties in the Suzuki-Miyaura cross-coupling reactions between aryl tosylates and aryl boronic acids, a first for such a NHC-Ni catalyst. Finally, mechanistic investigations led to the isolation of a well-defined oxidative addition product.
- Dorta, Reto,Duczynski, Jeremy,Moggach, Stephen A.,Sobolev, Alexandre N.,Stewart, Scott G.
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- Cross-Electrophile C(sp2)?Si Coupling of Vinyl Chlorosilanes
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The cross-electrophile coupling has become a powerful tool for C?C bond formation, but its potential for forging the C?Si bond remains unexplored. Here we report a cross-electrophile Csp2-Si coupling reaction of vinyl/aryl electrophiles with vinyl chlorosilanes. This new protocol offers an approach for facile and precise synthesis of organosilanes with high molecular diversity and complexity from readily available materials. The reaction proceeds under mild and non-basic conditions, demonstrating a high step economy, broad substrate scope, wide functionality tolerance, and easy scalability. The synthetic utility of the method is shown by its efficient accessing of silicon bioisosteres, the design of new BCB-monomers, and studies on the Hiyama cross-coupling of vinylsilane products.
- Duan, Jicheng,Kang, Shaolin,Liu, Xue-Yuan,Qi, Liangliang,Shu, Xing-Zhong,Wang, Ke,Xu, Guang-Li
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p. 23083 - 23088
(2020/12/09)
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- Aryl Radical Selectivity in Biphasic Systems
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Aryl radicals generated in the aqueous phase of biphasic mixtures have-regardless of a comparably low polarity- A strong preference to react with aromatic substrates in the aqueous phase and not to undergo phase-transfer into a lipophilic phase, independent from the presence of a surfactant. These results represent an important prerequisite toward future studies in biological systems, which typically consist of various compartments of either hydrophilic or lipophilic character.
- Altmann, Lisa-Marie,Fürst, Michael C. D.,Gans, Eva I.,Heinrich, Markus R.,Pratsch, Gerald,Zantop, Viviane
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supporting information
(2020/01/31)
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- Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
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Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp2)-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.
- Ishida, Takumi,Nishihara, Yasushi,Wang, Xiu,Wang, Zhenhua
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p. 7526 - 7533
(2020/06/27)
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- Decarbonylative Suzuki-Miyaura Cross-Coupling of Aroyl Chlorides
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Herein, we report a catalyst system for Pd-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of aroyl chlorides with boronic acids to furnish biaryls. This strategy is suitable for a broad range of common aroyl chlorides and boronic acids. The synthetic utility is highlighted in the direct late-stage functionalization of pharmaceuticals and natural products capitalizing on the presence of carboxylic acid moiety. Extensive mechanistic and DFT studies provide key insight into the reaction mechanism and high decarbonylative cross-coupling selectivity.
- Zhou, Tongliang,Xie, Pei-Pei,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 6434 - 6440
(2020/09/02)
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- Dual Nickel-/Palladium-Catalyzed Reductive Cross-Coupling Reactions between Two Phenol Derivatives
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Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance of phenols. Here, we report a dual nickel-/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2′-disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allows for straightforward late-stage functionalization, illustrated with examples such as ezetimibe and tyrosine.
- Xiong, Baojian,Li, Yue,Wei, Yin,Kramer, S?ren,Lian, Zhong
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supporting information
p. 6334 - 6338
(2020/09/02)
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- Cobalt-catalyzed C(sp2)?CN bond activation: Cross-electrophile coupling for biaryl formation and mechanistic insight
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Herein, we report a cross-electrophile coupling of benzonitrile derivatives and aryl halides with a simple cobalt-based catalytic system under mild conditions to form biaryl compounds. Even though the cobalt catalyst is able to activate the C(sp2)?CN bond alone, the use of the AlMe3 Lewis acid enhances the reactivity of benzonitriles and improves the cross-selectivity with barely any influence on the functional group compatibility. X-ray structure determination of an original low-valent cobalt species combined with catalytic and stoichiometric reactions reveals a catalytically active cobalt(I) species toward the aryl halide partner. On the other hand, experimental insights, including cyclic voltammetry experiments, suggest the involvement of a cobalt complex of a lower oxidation state to activate the benzonitrile derivative. Finally, density functional theory calculations support the proposed mechanistic cycle involving two low-valent cobalt species of different oxidation states to perform the reaction.
- Dorval, Céline,Tricoire, Maxime,Begouin, Jeanne-Marie,Gandon, Vincent,Gosmini, Corinne
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p. 12819 - 12827
(2020/11/18)
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- Nickel-Catalyzed Four-Component Carbocarbonylation of Alkenes under 1 atm of CO
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Transition-metal-catalyzed carbonylation is one of the most straightforward strategies to prepare carbonyl compounds. However, compared to well-established noble-metal-catalyzed carbonylation reactions, analogue coupling via base-metal, nickel catalysis has received less attention because of the easy formation of highly toxic and unreactive Ni(CO)4 species between Ni(0) and CO. To date, the use of inexpensive and widely available carbon monoxide (CO) gas for nickel-catalyzed carbonylation reaction remains challenging, and nickel-catalyzed four-component carbonylative reaction has not been reported yet. Here, we report a highly selective nickel-catalyzed four-component carbocarbonylation of alkenes under 1 atm (1 atm) of CO gas to efficiently achieve an array of complex carbonyl compounds, including fluorinated amino acids and oligopeptides of great interest in medicinal chemistry and chemical biology. This reaction relies on a nickel-catalyzed one-pot cascade process to assemble CO, arylboronic acids, and difluoroalkyl electrophiles across the carbon-carbon double bond of alkenes, paving a new way for base-metal-catalyzed carbonylative cascade reaction.
- Zhou, Minqi,Zhao, Hai-Yang,Zhang, Shu,Zhang, Yanxia,Zhang, Xingang
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supporting information
p. 18191 - 18199
(2020/12/04)
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- Crystal structure of ester Pd-NHC molecular complex and synthetic method
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The invention belongs to the technical field of catalysts, and discloses an ester Pd-NHC molecular complex and a synthetic method. The synthetic method comprises the steps that in a nitrogen atmosphere or air, a carboxylic ester ligand, divalent palladium ion metal salt, chloride, pyridine and a pyridine derivative solvent are placed in a conventional closed container and are heated for 10-2000 minutes; cooling is carried out to reach the room temperature, and vacuum evaporation is carried out on the solvent so as to obtain solid residues; the obtained solid residues are dissolved in a mixed solvent of dichloromethane and water, and separation is carried out through a separating funnel so as to obtain an organic phase; the organic phase is washed by using a 5% copper sulfate solution and saturated salt water and is dried by using anhydrous sodium sulfate, and vacuum evaporation is carried out on a solvent so as to obtain solid residues; and the obtained solid residues are recrystallized in a mixed solvent of chloroform and normal hexane so as to obtain Pd-NHC molecular crystals. According to the ester Pd-NHC molecular complex and the synthetic method, the carboxylic ester functional group modified Pd-NHC molecular complex is synthesized and a crystal structure of the Pd-NHC molecular complex is obtained.
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Paragraph 0032-0034
(2019/02/06)
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- Inorganic–organic hybrid nano magnetic based nickel complex as a novel, efficient and reusable nanocomposite for the synthesis of biphenyl compounds in green condition
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The carbon–carbon cross coupling reactions through transition-metal-catalyzed processes has been significantly developed for their important synthetic applications. A novel and fantastic nickel-based catalyst supported on bis (propyl malononitrile) (NiFe2O4@SiO2-BPMN-Ni) was easily prepared and evaluated as heterogeneous nanocatalyst in Suzuki cross coupling reaction of various aryl halides and phenylboronic acid. The catalyst prepared and characterized by using fourier transform infrared (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), thermo gravimetric analysis (TGA) and vibrating sample magnetometer (VSM) techniques. Compare to the previous works, this procedure have advantages such as easy workup, high yields of products, environmentally benign and short reaction times. The catalyst can be separated by external magnet and reused six times without any significant loss of activity which is an additional sustainable characteristic of this method. The products have been confirmed by spectroscopic and physical data such as; IR, 1H NMR, and melting point.
- Naeimi, Hossein,Kiani, Fatemeh
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p. 163 - 169
(2019/01/14)
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- Xantphos-Capped Pd(II) and Pt(II) Macrocycles of Aryldithiolates: Structural Variation and Catalysis in C-C Coupling Reaction
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The self-assembly of Xantphos-capped M(OTf)2 (M = cis-[M′(Xantphos)]2+ M′ = Pd, Pt) with bridging ligands 1,4-benezenedithiol or 4,4′-biphenyldithiol has been investigated. The reactions have yielded complexes [M{S(C6H4)nSH}]2(OTf)2 (I) and [M2{S(C6H4)nS}]2(OTf)4 (II) (n = 1 or 2). The equilibrium between I and II has been established in platinum complexes for n = 2, whereas the analogous Pd complex exclusively exist as II. These results are different from our previously reported dppe or triethyl phosphine-capped complexes which showed only type II. The same reaction with 1,3-benezenedithiol lead to the complex [M2(SC6H4SSC6H4S)](OTf)2 (III), containing a S-S bond between two thiolate ligands, formed via a complex of type I in solution. Characterization of the complexes was accomplished by NMR spectroscopy, UV-vis spectroscopy and mass spectrometry, and X-ray crystallography. Density functional calculations were performed to estimate the relative stability of three types of complexes. The palladium complexes are excellent catalysts in Suzuki C-C cross coupling reactions under mild conditions, and can be reused eight times without losing significant yield. The activity of the Pd catalysts derived from three dithiol ligand follows opposite trend of the stability as III > II > I. The comparative catalytic activity of the tetranuclear Pd complexes (II) of bis-phosphines of varied bite angles, including the structurally characterized [Pd2(dppf)2(SC12H8S)]2(OTf)4 has also been demonstrated.
- Mane, Pravin A.,Dey, Sandip,Pathak, Arup Kumar,Kumar, Mukesh,Bhuvanesh, Nattamai
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p. 2965 - 2978
(2019/03/02)
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- Nickel-metalated porous organic polymer for Suzuki-Miyaura cross-coupling reaction
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A new Ni(ii)-α-diimine-based porous organic polymer, namely Ni(ii)-α-diimine-POP, was constructed in high yield via the Sonogashira coupling reaction between the metallo-building block of Ni(ii)-α-diimine and 1,3,5-triethynylbenzene. Besides the high thermal and chemical stability, the obtained Ni(ii)-α-diimine-POP can be a highly active reusable heterogeneous catalyst to promote the Suzuki-Miyaura coupling reaction. The obtained results indicate that the Ni(ii)-α-diimine-POP herein is a promising sustainable alternative to the Pd-based catalysts for catalysing the C-C formation in a heterogeneous way.
- Dong, Ying,Jv, Jing-Jing,Li, Yue,Li, Wen-Han,Chen, Yun-Qi,Sun, Qian,Ma, Jian-Ping,Dong, Yu-Bin
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p. 20266 - 20272
(2019/07/10)
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- Nickel-catalyzed cross-coupling of: O, N -chelated diarylborinates with aryl chlorides and mesylates
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A practical nickel catalyst system consisting of readily available components, trans-NiCl(Ph)(PPh3)2/[Iprmim]I/K3PO4·3H2O in toluene, has been developed for efficient cross-coupling of 3-dimethylaminopropyl diarylborinates with aryl chlorides and mesylates. A small amount of water has been found to be crucial in achieving high efficiency in the system. The nickel catalyst system displayed remarkably higher activities to aryl chlorides and mesylates than the corresponding tosylates in cross-coupling with not only diarylborinates but also diarylborinic acids, arylboronic acids, anhydrides and trifluoroborates as indicated in control experiments. A variety of electronically various biaryls could be obtained in excellent yields by using 3-5 mol% loading of the nickel catalyst while sterically hindered biaryls were obtained in comparably lower yields.
- Ren, Chao,Zeng, Jingshu,Zou, Gang
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supporting information
p. 1589 - 1596
(2019/01/23)
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- Visible light-induced transformation of aldehydes to esters, carboxylic anhydrides and amides
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A transition metal- and organophotocatalyst free synthesis of esters, carboxylic anhydrides and amides from aldehydes induced by visible-light has been reported. The proposed methodology can be carried out by the use of sunlight or artificial visible light as a blue LED source. The methodology has a very broad applicability and the desired products are obtained in very satisfactory yields.
- Gaspa, Silvia,Raposo, Inês,Pereira, Leonor,Mulas, Gabriele,Ricci, Pier Carlo,Porcheddu, Andrea,De Luca, Lidia
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supporting information
p. 10711 - 10715
(2019/07/15)
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- METHOD FOR THE METAL-FREE PREPARATION OF A BIARYL BY A PHOTOSPLICING REACTION AND THEIR USES
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The present invention relates to a method for the metal-free preparation of a biaryl compound by a photosplicing reaction and its use in the preparation of chemical compounds, preferably of active ingredients e.g. in the fields of pharmaceuticals and agrochemicals. In particular, it refers to a method for the regiocontrolled preparation of a biaryl compound of formula (I): Ar-Ar' by photochemically reacting a precursor compound of formula (II): Ar-L-Ar' to form a biaryl compound of general formula: Ar-L-Ar' (II) → Ar-Ar' (I) wherein Ar and Ar', independently of each other, represent an unsubstituted or substituted C6-C20 aryl group or a heteroaryl group with 5–20 ring atoms selected from carbon, nitrogen, oxygen and sulfur, and L represents a group –X–Y–Z– as defined herein. The biaryl compounds are generally suitable as intermediates or key building blocks in a very broad spectrum of organic chemical syntheses and their respective utilities. Their use within the field of synthesis of active ingredients is an aspect of the invention, and their use in the preparation of pharmaceutically active ingredients is particularly preferred.
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Page/Page column 39; 47; 48
(2019/06/11)
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- Metal-Free Aryl Cross-Coupling Directed by Traceless Linkers
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The metal-free, highly selective synthesis of biaryls poses a major challenge in organic synthesis. The scope and mechanism of a promising new approach to (hetero)biaryls by the photochemical fusion of aryl substituents tethered to a traceless sulfonamide linker (photosplicing) are reported. Interrogating photosplicing with varying reaction conditions and comparison of diverse synthetic probes (40 examples, including a suite of heterocycles) showed that the reaction has a surprisingly broad scope and involves neither metals nor radicals. Quantum chemical calculations revealed that the C?C bond is formed by an intramolecular photochemical process that involves an excited singlet state and traversal of a five-membered transition state, and thus consistent ipso–ipso coupling results. These results demonstrate that photosplicing is a unique aryl cross-coupling method in the excited state that can be applied to synthesize a broad range of biaryls.
- Haensch, Veit G.,Neuwirth, Toni,Steinmetzer, Johannes,Kloss, Florian,Beckert, Rainer,Gr?fe, Stefanie,Kupfer, Stephan,Hertweck, Christian
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p. 16068 - 16073
(2019/11/28)
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- Alpha-diimine nickel metal organic ligand, porous organic polymer and application of porous organic polymer
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The disclosure provides an alpha-diimine nickel metal organic ligand, a porous organic polymer and application of the porous organic polymer. The porous organic polymer has a chemical structural formula as shown in the description. The porous organic polymer can be applied to preparation of a catalyst for catalyzing a Suzuki coupling reaction, and the catalyst has high catalytic activity, low cost, low usage amount and repeated use.
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Paragraph 0092-0093; 0106-0110
(2019/10/01)
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